feat: rename keep-notes to memento-note, migrate to PostgreSQL, fix MCP bugs

- Rename directory keep-notes -> memento-note with all code references
- Prisma: SQLite -> PostgreSQL (both app and MCP server schemas)
- Sync MCP schema with main app (add missing fields, relations, indexes)
- Delete 17 SQLite migrations (clean slate for PostgreSQL)
- Remove SQLite dependencies (@libsql/client, better-sqlite3, etc.)
- Fix MCP server: hardcoded Windows DB paths -> DATABASE_URL env var
- Fix MCP server: .dockerignore excluded index-sse.js (SSE mode broken)
- MCP Dockerfile: node:20 -> node:22
- Docker Compose: add postgres service, remove SQLite volume
- Generate favicon.ico, icon-192.png, icon-512.png, apple-icon.png
- Update layout.tsx icons and manifest.json for PNG icons
- Update all .env files for PostgreSQL
- Rewrite README.md with updated sections
- Remove mcp-server/node_modules and prisma/client-generated from git tracking

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

memento-note/app/actions/admin-settings.ts

@@ -0,0 +1,66 @@
+'use server'
+
+import { revalidatePath } from 'next/cache'
+import prisma from '@/lib/prisma'
+import { auth } from '@/auth'
+import { sendEmail } from '@/lib/mail'
+
+async function checkAdmin() {
+  const session = await auth()
+  if (!session?.user?.id || (session.user as any).role !== 'ADMIN') {
+    throw new Error('Unauthorized: Admin access required')
+  }
+  return session
+}
+
+export async function testSMTP() {
+  const session = await checkAdmin()
+  const email = session.user?.email
+
+  if (!email) throw new Error("No admin email found")
+
+  const result = await sendEmail({
+    to: email,
+    subject: "Memento SMTP Test",
+    html: "<p>This is a test email from your Memento instance. <strong>SMTP is working!</strong></p>"
+  })
+
+  return result
+}
+
+export async function getSystemConfig() {
+  await checkAdmin()
+  const configs = await prisma.systemConfig.findMany()
+  return configs.reduce((acc, conf) => {
+    acc[conf.key] = conf.value
+    return acc
+  }, {} as Record<string, string>)
+}
+
+export async function updateSystemConfig(data: Record<string, string>) {
+  await checkAdmin()
+
+  try {
+    // Filter out empty values but keep 'false' as valid
+    const filteredData = Object.fromEntries(
+      Object.entries(data).filter(([key, value]) => value !== '' && value !== null && value !== undefined)
+    )
+
+
+
+    const operations = Object.entries(filteredData).map(([key, value]) =>
+      prisma.systemConfig.upsert({
+        where: { key },
+        update: { value },
+        create: { key, value }
+      })
+    )
+
+    await prisma.$transaction(operations)
+    revalidatePath('/admin/settings')
+    return { success: true }
+  } catch (error) {
+    console.error('Failed to update settings:', error)
+    return { error: 'Failed to update settings' }
+  }
+}